1. Field of the Invention
The present invention relates to agricultural tillage implements, and, more particularly, to agricultural field cultivators.
2. Description of the Related Art
Farmers utilize a wide variety of agricultural tillage implements to prepare soil for planting. Some such implements include two or more sections coupled together to perform multiple functions as they are pulled through fields by a tractor. For example, a field cultivator is capable of simultaneously tilling soil and leveling the tilled soil in preparation for planting. A field cultivator has a frame that carries a number of cultivator shanks with shovels at their lower ends for tilling the soil. The field cultivator converts compacted soil into a level seedbed with a consistent depth for providing excellent conditions for planting of a crop. Grass or residual crop material disposed on top of the soil is also worked into the seedbed so that it does not interfere with a seeding implement subsequently passing through the seedbed.
A field cultivator as described above may also include an optional rear auxiliary implement for finishing the seedbed for seeding. For example, a rear auxiliary implement may include a spike tooth harrow, spring tooth harrow, rolling (aka. crumbler) basket, drag tines, etc., or any combination thereof.
Such tillage implements have been constructed with large lateral spans to realize greater efficiency and speed. Tillage implements with significant lateral spans often have many different joints and are usually articulated to enable transport to and between fields. When such large tillage implements are used, it is important to maintain uniform and level tool contact with the soil. The desirable outcome is a uniform physical depth of the tillage and a uniform entry of the disk blades or harrows into the soil. The need to have a level positioning of the implement is made more challenging with the common use of hydraulic actuators which control the depth of penetration of the disk blades or other tools. In current practice, hydraulic actuators are connected in series and it is possible through normal operation for hydraulic fluid leakage to make the actuators out of sync with one another. In addition, field conditions, such as wheel loading and other variables, require an adjustment to the synchronization of the different sections of the tillage implement, thereby requiring the operator to dismount from a tractor and make manual adjustments.
It is current practice to partially counter this occurrence by fully elevating the implement to the point where bypass lands in the actuators allow full flow of hydraulic fluid to pass through the actuators and again synchronize the multiple units. However, this adds an additional step to the operation, particularly in the field, thereby decreasing the efficiency and speed with which the particular task is accomplished.
Further, as agricultural tillage implements become wider and wider over time, it becomes more difficult to keep the transport size of the implement within manageable limits. It also becomes more difficult to convert the agricultural tillage implement from an operating configuration to a transport configuration, or vice versa, without requiring too much time and difficulty on the part of the operator. It is desirable for the agricultural tillage implement to be converted from one mode to the other while the operator remains within the operator cab, through the use of hydraulics or other actuators. It is also desirable for the agricultural tillage implement to remain within certain geometric constraints so that it is not necessary to use a separate “escort vehicle” or the like when traveling on public roads. It is further desirable that any hydraulic system used to convert the agricultural tillage implement from one mode to the other be as efficient, robust, as simple as possible, and operate in a coordinated fashion without excessive intervention by an operator.
What is needed in the art therefore, is an efficient apparatus and method for maintaining agricultural implements in a level position relative to the soil by individual adjustment but with a minimum of hydraulic lines. Further needed is such an apparatus and method that coordinates the motions of the agricultural implement.